A compound semiconductor is not made of a single element such as silicon (Si) and germanium (Ge) and is formed by a combination of two or more kinds of elements to operate as a semiconductor. Various kinds of compound semiconductors have been currently developed and used in various fields. The compound semiconductors are typically used for a light emitting element, such as a light emitting diode and a laser diode, and a solar cell using a photoelectric conversion effect, a thermoelectric conversion element using a Peltier effect, and the like.
A compound semiconductor solar cell uses a compound semiconductor in a light absorbing layer that absorbs solar light and generates electron-hole pairs. The light absorbing layer is formed using a III-V compound semiconductor such as GaAs, InP, GaAlAs and GaInAs, a II-VI compound semiconductor such as CdS, CdTe and ZnS, a compound semiconductor such as CuInSe2, and the like.
A plurality of compound semiconductor solar cells each having the above-described configuration is connected in series or in parallel to configure a solar cell module.
FIG. 1 schematically illustrates a configuration of a compound semiconductor solar cell according to a related art.
A compound semiconductor solar cell shown in FIG. 1 includes a back electrode 10 formed of a metal layer, a semiconductor layer 20 formed on the back electrode 10, and a plurality of grid electrodes 30 formed on the semiconductor layer 20. The semiconductor layer 20 is formed of a compound semiconductor and is partially removed to expose one end (a right end in FIG. 1) of the back electrode 10.
The adjacent compound semiconductor solar cells each having the above-described configuration are connected to each other in series and/or in parallel in the solar cell module. For example, as shown in FIG. 2, one end of a conductive connection member 40 is attached to a back electrode 10 of a first solar cell by soldering, and the other end of the conductive connection member 40 is attached to a grid electrode 30 of a second solar cell by soldering. Thus, the plurality of solar cells is connected in series.
However, because the soldering for attaching the conductive connection member 40 to the corresponding electrode is performed at a high temperature, the semiconductor layer 20 may be deformed by heat generated in an attachment process using the soldering.
The back electrode 10 and the grid electrode 30 respectively attached to both ends of the conductive connection member 40 are respectively disposed at a front surface and a back surface of the semiconductor layer 20 with the semiconductor layer 20 interposed therebetween. Therefore, it is difficult to perform the attachment process using the conductive connection member 40 due to a height difference between the back electrode 10 and the grid electrode 30.